diff options
Diffstat (limited to 'kernel/bpf')
| -rw-r--r-- | kernel/bpf/btf.c | 37 | ||||
| -rw-r--r-- | kernel/bpf/helpers.c | 11 | ||||
| -rw-r--r-- | kernel/bpf/syscall.c | 14 |
3 files changed, 49 insertions, 13 deletions
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 37779ceefd09..66fad7a16b6c 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -3551,12 +3551,17 @@ static int btf_find_field(const struct btf *btf, const struct btf_type *t, return -EINVAL; } +extern void __bpf_obj_drop_impl(void *p, const struct btf_record *rec); + static int btf_parse_kptr(const struct btf *btf, struct btf_field *field, struct btf_field_info *info) { struct module *mod = NULL; const struct btf_type *t; - struct btf *kernel_btf; + /* If a matching btf type is found in kernel or module BTFs, kptr_ref + * is that BTF, otherwise it's program BTF + */ + struct btf *kptr_btf; int ret; s32 id; @@ -3565,7 +3570,20 @@ static int btf_parse_kptr(const struct btf *btf, struct btf_field *field, */ t = btf_type_by_id(btf, info->kptr.type_id); id = bpf_find_btf_id(__btf_name_by_offset(btf, t->name_off), BTF_INFO_KIND(t->info), - &kernel_btf); + &kptr_btf); + if (id == -ENOENT) { + /* btf_parse_kptr should only be called w/ btf = program BTF */ + WARN_ON_ONCE(btf_is_kernel(btf)); + + /* Type exists only in program BTF. Assume that it's a MEM_ALLOC + * kptr allocated via bpf_obj_new + */ + field->kptr.dtor = (void *)&__bpf_obj_drop_impl; + id = info->kptr.type_id; + kptr_btf = (struct btf *)btf; + btf_get(kptr_btf); + goto found_dtor; + } if (id < 0) return id; @@ -3582,20 +3600,20 @@ static int btf_parse_kptr(const struct btf *btf, struct btf_field *field, * can be used as a referenced pointer and be stored in a map at * the same time. */ - dtor_btf_id = btf_find_dtor_kfunc(kernel_btf, id); + dtor_btf_id = btf_find_dtor_kfunc(kptr_btf, id); if (dtor_btf_id < 0) { ret = dtor_btf_id; goto end_btf; } - dtor_func = btf_type_by_id(kernel_btf, dtor_btf_id); + dtor_func = btf_type_by_id(kptr_btf, dtor_btf_id); if (!dtor_func) { ret = -ENOENT; goto end_btf; } - if (btf_is_module(kernel_btf)) { - mod = btf_try_get_module(kernel_btf); + if (btf_is_module(kptr_btf)) { + mod = btf_try_get_module(kptr_btf); if (!mod) { ret = -ENXIO; goto end_btf; @@ -3605,7 +3623,7 @@ static int btf_parse_kptr(const struct btf *btf, struct btf_field *field, /* We already verified dtor_func to be btf_type_is_func * in register_btf_id_dtor_kfuncs. */ - dtor_func_name = __btf_name_by_offset(kernel_btf, dtor_func->name_off); + dtor_func_name = __btf_name_by_offset(kptr_btf, dtor_func->name_off); addr = kallsyms_lookup_name(dtor_func_name); if (!addr) { ret = -EINVAL; @@ -3614,14 +3632,15 @@ static int btf_parse_kptr(const struct btf *btf, struct btf_field *field, field->kptr.dtor = (void *)addr; } +found_dtor: field->kptr.btf_id = id; - field->kptr.btf = kernel_btf; + field->kptr.btf = kptr_btf; field->kptr.module = mod; return 0; end_mod: module_put(mod); end_btf: - btf_put(kernel_btf); + btf_put(kptr_btf); return ret; } diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index f9b7eeedce08..77d64b6951b9 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1896,14 +1896,19 @@ __bpf_kfunc void *bpf_obj_new_impl(u64 local_type_id__k, void *meta__ign) return p; } +void __bpf_obj_drop_impl(void *p, const struct btf_record *rec) +{ + if (rec) + bpf_obj_free_fields(rec, p); + bpf_mem_free(&bpf_global_ma, p); +} + __bpf_kfunc void bpf_obj_drop_impl(void *p__alloc, void *meta__ign) { struct btf_struct_meta *meta = meta__ign; void *p = p__alloc; - if (meta) - bpf_obj_free_fields(meta->record, p); - bpf_mem_free(&bpf_global_ma, p); + __bpf_obj_drop_impl(p, meta ? meta->record : NULL); } static void __bpf_list_add(struct bpf_list_node *node, struct bpf_list_head *head, bool tail) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index cc4b7684910c..0684febc447a 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -659,8 +659,10 @@ void bpf_obj_free_fields(const struct btf_record *rec, void *obj) return; fields = rec->fields; for (i = 0; i < rec->cnt; i++) { + struct btf_struct_meta *pointee_struct_meta; const struct btf_field *field = &fields[i]; void *field_ptr = obj + field->offset; + void *xchgd_field; switch (fields[i].type) { case BPF_SPIN_LOCK: @@ -672,7 +674,17 @@ void bpf_obj_free_fields(const struct btf_record *rec, void *obj) WRITE_ONCE(*(u64 *)field_ptr, 0); break; case BPF_KPTR_REF: - field->kptr.dtor((void *)xchg((unsigned long *)field_ptr, 0)); + xchgd_field = (void *)xchg((unsigned long *)field_ptr, 0); + if (!btf_is_kernel(field->kptr.btf)) { + pointee_struct_meta = btf_find_struct_meta(field->kptr.btf, + field->kptr.btf_id); + WARN_ON_ONCE(!pointee_struct_meta); + field->kptr.obj_drop(xchgd_field, pointee_struct_meta ? + pointee_struct_meta->record : + NULL); + } else { + field->kptr.dtor(xchgd_field); + } break; case BPF_LIST_HEAD: if (WARN_ON_ONCE(rec->spin_lock_off < 0)) |